Gun Review: Primary Weapons System Modern Musket 14.5″ in .223 Wylde

Review: Primary Weapons Systems Modern Musket 14.5″ in .223 Wylde

As I mentioned in my article about the Diablo, I was able to get access to a couple of sexy new rifles from Primary Weapons Systems. The Modern Musket being one of them. Walt and Luke from BMC Tactical ( hooked me up with a demo “pre-release” version (obviously they are somewhat available now).

The “Modern Musket” is Primary Weapons Systems’ first foray into making a Direct Impingement style AR. PWS is best known for their Long-Stroke Piston rifles (and just like the Diablo writeup, this article is not intended to extoll the virtues of one platform over another). What I will say is that PWS puts the same level of professionalism and technical expertise into their craftsmanship of this direct impingement weapon as in any of the others that I have had the pleasure to shoot.

You may see a couple of recycled bits from the Diablo review, because, well, both the Diablo and Modern Musket use some of the same components. And I ran them at the same time.






The model I got to play with was the 14.5″ version. Primary Weapons Systems also sells a version with 16″ barrel (all of the other components being the same).

The rifle comes as a complete “out of the box” solution. Meaning it is intended to run as a great performance rifle with no modifications.

Buffer System

The Buffer Tube, machined from a single piece of 6061 aluminum, is one of the important features. It has a lip that extends into the receiver and provides support against carrier tilt (not as important since this is a direct impingement system). It has four drain holes to prevent hydrostatic locking of the reciprocating buffer, and is fluted to shed debris. It uses a standard carbine length H2 buffer and spring. The difference between this buffer and more commonly available ones is that the buffer itself is a tungsten weight housed in a steel body, coated in nickel Teflon. So it is both heavier and slicker.



The tube uses a hex bolt to help align the tube to the lower receiver and two locking allen heads at the top to keep the buffer tube from rotating on the lower. If you are not familiar with the PWS buffer tube, what this boils down to is: No. More. Castle. Nut. On the Modern Musket this buffer tube also has a six-position stop, allowing for standard AR collapsible stocks to be attached.



The bolt carrier group is PWS’s Enhanced Bolt Carrier. It is precision machined and isonite treated (just like the barrel). The bolt carrier has increased mass (it is significantly thicker than a standard BCG) which should both extend dwell time and slightly delay unlock. What this means is that it allows the chamber pressure to be reduced making extraction easier and thus accumulating less wear and tear on the system.


There are a number of gaps and channels between skid pads on the BCG which provides fewer points of contact. With fewer points there should be less overall friction, and this should reduce the accumulation of residue and grime, as well as further reduce wear and tear.

The action uses a low profile gas block that is machined in-house from heat-treated tool steel. It is also lighter than other low profile gas blocks. It looks to be almost half the length of most other ones I’ve encountered.

The charging handle is the BCM Gunfighter, one I personally think is one of the better ones out there (feel free to troll or support that opinion in the comments below).

The trigger is ALG Defense’s Quality Mil-Spec trigger, and was set somewhere around 6.5 lbs (if I had to guess).



The included Lucid HD7 (a red dot sight) is stated to be waterproof, shock proof and fog proof. It also has four different reticles you can cycle through (which is gimmicky in my option; no offense to the CoD fans out there). It is also covered by a lifetime warranty.


It does not come with any “iron sights” so if you want a sighting system that doesn’t need batteries, you will need to add it.


The rail is mounted on the Primary Weapon System designed full-length free-floating hand guard (using the KeyMod system). The quad rail system is not proprietary and can be installed really on any AR platform. It is a modular quad rail; you can remove the rail without having to replace the entire component. The rail also had quick disconnect sling swivel mounts fore and aft.


Installed were Magpul MOE buttstock, the Magpul trigger guard and Magpul pistol grip (with integral storage).



The barrel is the Primary Weapons Systems’ “standard” Isonite QPQ treated and features a 1:8 twist. If you are not familiar with Isonite treatment, the tl;dr is that you take a barrel, give it a salt bath to nitrocarburize it (producing a layer of iron nitride), polish the hell out of it, and then give it a nice soak back in the salt bath after which you rinse it and oil it (which is eerily similar sounding to the pedicures my wife gets).

Muzzle Device

The muzzle device is the PWS Triad 556. It actually offers true flash suppression (compared to the CQB on the Diablo, though, what doesn’t?). It also really reduces muzzle rise. The other “hot” feature is that it is a suppressor compatible mount (for suppressors compatible with A2 flash hiders).



I brought my wife and a couple of friends (including Thomas Gomez, another TFB writer), because shooting is always better in groups.

For this shoot, I broke out some of my .223 stores and went through a little north of 600 rounds. Again, it was nice, dirty Russian surplus (though Thomas Gomez really wanted me to shoot some of his prissy Federal XM193)

We shot from about 50 feet to 6 feet.

I initially ran a couple of PMags through it to get a feel for how it shot, and following that we ran a whole bunch of magazines that Thomas brought (breakdown of that in the reliability section).

Just like the Diablo, we ran the gun as fast as we could load the magazines, and it also eventually got too hot to hold without gloves.


Thomas brought out a number of magazines for our shoot. It is definitely useful to try a bunch of different ones out as sometimes weapons are a bit finicky about what they accept due to manufacturing tolerance differences. In this case we used both Generation 1 (and Generation 3) 30 round Magpul PMags as well as a 20 round Generation 1. A current generation USGI magazine with the tan anti-tilt follower. A BCM GI Magazine without an anti-tilt follower. A Troy Battle Mag. And a crappy 20 round Thermold Magazine. We did have a couple of misfeeds from the Gen 1 PMag and the Troy magazine.

As I mentioned before, I ran around 600 rounds of dirty Tula through it, and I did not clean, nor lubricate, the weapon once.


Not once did I have a problem with feeding or round ejection with the .223 rounds despite shooting in a couple of awkward positions, and while on the move. We basically ran the same drills with the Modern Musket as we did with the Diablo. Thomas did have a malfunction with a couple rounds of XM193. Not entire sure why, though I’d like to claim that the rifle really likes the taste of the dirty Russian ammo and not the snooty Federal. I would like to also put out that the XM193 was somewhere around the 14th magazine of ammo.


The Primary Weapons Systems Modern Musket is a well-built, solidly performing AR. PWS has thoughtfully assembled a rifle from a number of high-quality components and out of the box it is “range ready”.

If you look at the rifle “big picture” what you will see is that the design and components are done in such a way as to really increase the longevity of the rifle. While you should still perform routine maintenance, the components themselves are set up to give you years of life. My biggest complaint (and the only one I can come up with) is that it doesn’t come with iron sights. I was impressed enough that I am adding one to my harem of rifles.

Note: It is so well designed and the quality is such that Albuquerque Police Department recently contracted to get 350 units of this exact model to outfit qualified officers.


  • Potentially huge lifespan on barrel (Isonite QPQ)
  • “Range ready”
  • Solid optics
  • Beefy internal components
  • .223 Wylde
  • Direct Impingement Gas (if you like DI Gas Systems)


  • Direct Impingement Gas (if you hate DI Gas Systems)
  • No iron sights.


  • Model Number: DI-14/DI-16
  • Action Type: Semi-automatic
  • Caliber: .223 Wylde
  • Capacity: 30 rounds
  • Length: 31.4″/33″
  • Barrel Length: 14.5″/16″ Isonite QPQ Treated
  • Weight: 6lbs, 7oz/ 6lbs, 12oz
  • Sights: Lucid HD7
  • Price: Street ~$1499 (all variants)

Tom is a former Navy Corpsman that spent some time bumbling around the deserts of Iraq with a Marine Recon unit, kicking in tent flaps and harassing sheep. Prior to that he was a paramedic somewhere in DFW, also doing some Executive Protection work between shifts. Now that those exciting days are behind him, he has embraced his inner “Warrior Hippie” and assaults 14er in his sandals and beard, or engages in rucking adventure challenges while consuming craft beer. To fund these adventures, he writes medical software and builds websites and mobile apps. His latest venture is as one of the founders of; a search engine for all things gun related. He hopes that his posts will help you find solid gear that will survive whatever you can throw at it–he is known (in certain circles) for his curse…ahem, ability…to find the breaking point of anything.


  • Nicks87

    I think we are getting to the point soon where AR manufacturers can no longer justify $1500+ for a DI rifle unless they are one of the big names (Noveske, BCM, LMT, Colt, KAC, etc). I’m sure this rifle works as advertised but why would I buy a PWS when I could get one of the aforementioned rifles for a couple hundred more or buy a cheaper rifle and a more high quality optic? Soooo many options out there for AR15 style rifles right now I dont see this one turning any heads.

    • NDS

      PWS is in the same conversation as Noveske, KAC and BCM. I do not own a Colt or LMT so I can’t speak from personal experience for those two.

      • Nicks87

        They might be, but as a consumer I would probably go with a more well known manufacturer. Just because it looks good on paper doesnt mean its on the same level as those rifles that have already been put through their paces. I guess time will tell but with the amount of quality ARs out there and the market for them slowing down I see companies having to drop their prices sooner than later if they want to compete.

    • Dan

      Sure AR manufacturers can justify the high prices. They will just invent new space age barrel treatments and continue fixing problems the majority of us have never had with our rifles.
      I absolutely refuse to even look at my AR with it’s non anti tilt carrier, non isomelonitkryptoniumcarbonite coated barrel lack of debris shedding buffer tube. Super micro skid pad titanium carbide diamond dust BCG. I’m surprised it will even shoot bullets straight!

      • Nicks87

        I know, you might as well just toss it in the trash lol.

  • 1leggeddog

    Now THIS is a well written review!

  • Zachary marrs

    Whats the gas system length on the 16″? If its carbine, they need to roll back the “di done right” slogan

  • SS Totenkopf

    derp-“Modern Musket”-derp.

  • claymore

    Why a 14.5″ barrel in SEMI? Makes no sense.

    • Zachary marrs

      As opposed to what, lever action?

      14.5 allows for the proper dwell time for carbine length gas systems

      • claymore

        AH Duhhh why would someone pay $200NFA tax for just a short barrel when a 16″ bareel works just as well. One could pay the $200 tax and get a selectfire version AND a short barrel combined.

        • Nicks87

          I’m guessing the muzzle device is welded/pinned making it part of the barrel and a legal 16in. long.

          • claymore

            Then again WHY?

          • Zachary marrs

            To allow the proper use of the carbine length gas system

          • claymore

            !6″ works less good providing more gasses?

          • Zachary marrs

            If you have a 16 inch bbl, you want to run a mid length gas system in order to keep the dwell time (the length of barrel between the gas port and muzzle) as close as possible to the dwell time of a 20 inch barrel using a rifle length gas system. Using a 14.5 barrel with a carbine length gas system is ideal, and it is as close to a military m4 without joining the army

          • claymore

            But but the PORT taking off the gasses is in the exact same spot on 16 & 14 inch barrels. so same difference.

          • Zachary marrs

            Ughhh. Dwell time is the measurement if how long the bullet has to travel after passing the gas block and leaving the barrel.

            16″ barrels using the carbine gas system are over gassed, and will decrease part lifetime

          • claymore

            By how much? You can’t even measure it effectively but still it works just like the designers want it too. Get parts beating (not hardly) then balance it with buffer weight.

            The point stands no benefit for the price.

          • Zachary marrs

            Measures what effectively? Parts life? You cant seriously claim a gun that will beat itself up will last as long as gun that doesn’t.

            Pws isn’t the only company putting out 14.5 barrel, bcm, spikes tactical, noveske, and psa are some of the few

          • claymore

            Yep and used on selectfire versions. Everybody on the latest fag. So you actually have no experience with 16″ barrels or you would know they don’t beat itself up. Ours were used for years with a couple hundred rounds through them every week and no parts replacement need worked just as designed.

            No governemnt agencies involved with supplying service members making the switch so the market for these are weekend shooters without too much worry about parts wearing out for several years if then.

          • Zachary marrs

            What? Calm down space ranger.

            It beats up parts more, cant deny that. The military uses the 14.5, my local pd uses whatever they want, several of them still have m1 carbines in their trunk, the others use eirher 14.5 or 16s.

            I have a 16″ barrel witha a mid length gas system, which is the ideal gas tube length

            Do you work for battle rifle company?

          • claymore

            Why the disparagement we were having an adult discussion? Not anymore we aren’t little boy.

          • Zachary marrs

            You are trying to argue that a improperly specced rifle is no better than a properly specced one. You don’t even know what dwell time is.

            Also, what? Missing a few commas in that sentence.

            Way to ignore my other points, bro.

          • claymore

            Here you go sonny. these guys use scientific testing to prove your bud was in correct in his guessing LOL.

            Try debating this with the experts at Janes. Note the INCREASE of pressure using a 14.5 inch barrel vs a 16 inch barrel. That shows that a 14.5 inch barrel BEATS THE COMPONENTS MORE than using a 16 inch barrel.

            replace the (DOT) with a .


          • Zachary marrs

            Give me a working link, then we will talk.

          • claymore

            Incorrect yet again. The bud you said had all the knowledge in the world that you used to try and fail at your point. Go back and re-read your posts.

            Colt made the decision to use carbine length with a 16 icn barrel guess you think they were incorrect ROFLMAO

            The Army wanted a shorter WEAPON (not gun) that they could use with the issued bayonet that is why they went with 14.5

          • Zachary marrs

            You need to get back on your meds.

          • claymore

            Good kindergarten reply sonny LOL.

          • Zachary marrs

            I hope you know that your link proves nothing, other than sub 14.5″ barrels are not worth it, only once did they mention gas tube length, towards the end where they said 14.5 inch barrels with carbine gas systems allow for the proper dwell time.

            WTF are you even trying to say?

          • claymore

            No need to you can’t even understand the article what am I supposed to do lead you by the hand?

            Try again where they demonstrate that the shorter the barrel the MORE pressure POUNDING on the parts. And the 16″ has LESS pressure AND more velocity. The 14.5 just barley has enough velocity to be lethal.

            Your whole rant is incorrect.

          • Zachary marrs

            Barly? I love barley, can I have some?
            The difference in pressure is so minimal, it doesn’t matter.

            If you want a carbine gas system, get a 14.5 inch barrel,

            If you want a middie gas system, get a 16″ bbl

            If you want a rifle gas system, get a 20″

          • claymore

            Little guy you are having reading comprehension problems and cherry picking the facts once again (you know you are losing the discussion when you have to distort the data LOL). It said the 14.5 is better than SHORTER BARRELS only.

            And that the 14.5 BEATS the components harder than the 16″. Guess you and your bud were proven wrong once again.

            Others can read you know they know when you are cherry picking because they are more intelligent than yourself.

            Once again COLT, you know the ones that actually make them, think the 16″ barrel works just fine with the carbine gas system. NO WAIT you better contact them and let them Be sure to let us know how that goes LOL.

            You call that pressure differential minimal ROFLMAO dude you are compensating for being a fan boy LOL

          • Zachary marrs

            If you remember one of my earlier comments, you will see where I said I have a 16″ barrel with a middy gas system.

            Where can I get some of your barley?

          • claymore

            Well Colt thinks they work fine and have been building them like that for 40 years LOL. Like I said contact them and tell them you think they have been wrong for 40 years LOL.

            NEVER EVER said they were crap what I did say that started this whole thing was this was a waste of money to use semi. YOU insisted 16 inch barrels were harder on parts and we now have proof that is incorrect the 14.5 is the one harder on parts.

            Yep the doggies use them but the Marines don’t (in normal line units) Ask them why LOL.

          • Zachary marrs

            16″ barrwls are rougher on parts if the barrel is using a carbine gas system, and your link never tested the effects the gas tube has, and you’ve never address this in any of your comments

          • claymore

            Totally incorrect you are having reading comprehension problems there goober. Just go re-read the article or get your mom to try and explain it to you.

        • Zachary marrs

          Pws cant make select fire, plus if you get the proper flash hider/muzzle brake pinned and welded you don’t have to worry about nfa

          • claymore

            Then you have a shorter barrel the same length again why?

          • Zach

            There are benefits to shorter barrels other than the dwell time. Having a shorter barrel is advantageous in home defense,or any task that requires you to be able to maneuver in tight spaces. The goal of a short barrel is simple: to allow for a more compact gun.

          • claymore

            BUT it is still as long as the 16 inch with the flash hider permanently attached.

          • Zachary marrs

            The a2 bird cage adds like an inch to the barrel

          • claymore

            Wow a whole inch goodness me that is a severe penalty in length. Can’t you actually look up the correct specs? rolls eyes

            What ever are we going to do if THEY apply one on their 14.5 incher?

          • Zachary marrs

            Its 16″ vs 17″, plus if you want to run a carbine gas tube, a 14.5″ barrel is the proper length

          • claymore

            Then why did they also make them in 10 and 11 inch versions? So you keep saying Colt was wrong… ROFLMAO

          • Zachary marrs

            I never said a word about colt being wrong

          • claymore

            Who said? What does correct specs mean?

          • Zachary marrs

            Ok, correct is a bit too strong a word, perhaps, “optimal” is a better choice

          • pineneedle

            Your ignorance is showing.

          • claymore


          • Zachary marrs

            Well, #1, you don’t know what dwell time is
            #2, you can’t even provide a working link to a website that backs you up #3 you forget that the a2 flash hider adds length to the 16″ barrel, and #4 you seem to have a sever misunderstanding of nfa rules/regulations

          • claymore

            Little dude take out the (DOT) and add a peroid.

            Link works fine and I would post it for you low intelligent guys so you don’t have to do anything but you know no hot linking.

            LOL so you add a miniscule length it’s still the same as a 14.5 with permanent flash hider and it still BEATS UP YOUR WEAPON MORE then 16 inches. That is all you got sonny?

            For your edification I was a SOT for ten years and bought, sold, and shot more NFA weapons than you will hold in your entire life (how’s that for comma use?)

          • Zachary marrs

            OHH BIG DUDE SOT don’t mean dick pal

          • claymore

            LOL know more about NFA weapons than you ever will sonny. LOL you can’t even make a simple link work.

          • Zachary marrs

            You thought that you had to get a 200 dollar tax stamp for a 1.45 inch barrel, and you didn’t know what dwell time is, and you cant even give aa working link

          • claymore

            from the atf site:

            If the subsequent owner buys the receiver as a GCA firearm and installs a barrel less than 16 inches in length (SBR) or 18 inches in length (SBS), the firearm would be subject to a $200 making tax and registration under the NFA by the manufacturer or maker of the SBR or SBS. Because registration depends upon the stated intent of the applicant, there is no provision to allow registration of a NFA firearm by anyone other than the maker or manufacturer.

          • Zachary marrs

            You can get a 14.5 inch barrel without a tax stap idiot, it can stay 14.5 inches if you put it on a pistol build, but if you are going to put it on a rifle, you will need a welded muzzle device or go nfa

          • claymore

            Little guy why would anyone buy a barrel and not install it? And why buy a shorter barrel then make it longer LOL.

          • Zachary marrs

            Thats it im done, you are just being a shit head now.

            You only need a tax stamp if it goes on a rifle lower. STOP BEING AN IDIOT

          • claymore

            Nice childish response there jr. And care to take a guess how many rifles there are compared to pistols?

          • claymore

            And if you buy one AND have a rifle lower in the same space that would be a violation like buying a parts kit for a suppressor and have tubing but not yet put together HUMMM?

          • Zachary marrs

            People have asked the atf this question, and they have said that it is ok if they are in a separate room.

            In any case, its still a grey area

          • claymore

            Yea sure just like having an AR and M-16 parts.

          • claymore

            Just give us the definition of readily convertible. Not much easier than popping two pins and installing.

          • Zachary marrs

            Its a grey area, at least as far as the atf is concerned, you could ask them this question again and they’d probably give you a different answer.

            In any case, the atf seems to care about the intent to manufacture, so id guess* that as long as you plan to go sbr, build a pistol, or get a muzzle device permanently attached, its ok

            *you really cannot be certain when it comes to the atf, but almost all of their recent decisions have based on the intent to manufacture.

          • Zachary marrs

            Give me a working link, just copy and paste

          • claymore

            Try debating this with the experts at Janes. Note the INCREASE of pressure using a 14.5 inch barrel vs a 16 inch barrel. That shows that a 14.5 inch barrel BEATS THE COMPONENTS MORE than using a 16 inch barrel.

            replace the (DOT) with a .


  • Zach

    I’d like to point out that the muzzle device pictured is not the PWS Triad, but rather the PWS FSC-556. Other than that, nice review. I’d like to see a followup on accuracy at 100 yards and further.

  • WFDT

    A little short for a musket. Put a forty-inch barrel on it and we’ll talk.

  • Cornelius Carroll

    When using brass after steel and before cleaning there’s a pretty decent chance you’ll get a FTE or a stuck case. Using brass then steel usually isn’t an issue. The steel doesn’t expand as much as brass thus not creating a proper seal. This allows some residue to blow back into the chamber. For steel rounds this isn’t a big deal because, again, it doesn’t expand as well as brass and thus doesn’t exert as much outward pressure on the chamber walls. Brass does expand, however, and if the chamber has somewhat fresh gunpowder residue in it will adhere to the brass causing the case to stick. Best case is usually an FTE worst case is a stuck case. Really nothing to do with the AR, piston, di, etc just has to do with steel vs brass. I suppose a fluted chamber ala HK 91 would probably nullify this problem.

    • Thomas Gomez

      Interesting. I am going to have to test that on one of my “beater Ar-15’s”. Thanks for the tip.

      Hope this finds you well!

  • Russian surplus .223?

  • JT

    Still don’t get the “modern musket” thing unless these things will be smoothbore

  • I think the whole “Modern Musket” spheal is just PR-speak. And, how expensive is 223 Wylde? I haven’t heard of it, so I don’t think it’s gonna be cheap.

    • Zachary marrs

      Layman’s terms, its a tighter specced 5.56 nato chamber, you can shoot both .223 and 5.56×45 in it

  • Charles Applegate

    ABQ PD has qualified officers?